In order to find a person or vessel lost at sea or on land, an aircraft must follow a pattern describing a search pattern, or SAR pattern, which will be referred to as a SAR trajectory, or more simply a SAR pattern, hereinafter. The aim of this predetermined trajectory is to optimize the trajectory of the aircraft in order to cover the entire search area. Various trajectory patterns exist depending on the search conditions.
The solutions of the prior art rest on the use of the flight management system, which will be referred to as the FMS hereinafter.
The SAR trajectory patterns form an integral part of the FMS, which is responsible for the aircraft following a programmed trajectory.
However, all technical parameters are manually entered by the pilot, these parameters being, in particular, the position of the entry point of the trajectory, the position of the exit point, the separation between two branches of the trajectory, the width and the length, the azimuth (orientation with respect to north).
In particular, the drawbacks of these solutions are:
time wasted by the operator responsible for calculating the technical parameters. Specifically, even with an FMS, these parameters are still calculated manually and these calculations are not simple, since they depend on multiple technical, geographic or environmental parameters such as the geographic area to be covered, the transit time, the altitude of the aircraft, the weather, the sea conditions or the flight speed;
a lack of real-time graphical representation: the operator enters all parameters one by one, then this trajectory is incorporated into the flight management. If this does not visually correspond to the expectations of the operator, the operator must modify the values one by one. This lack of representation leads to wasted time for the operator, who must re-enter a trajectory if he or she considers the latter not to be optimal with respect to the search area;
a lack of direct relationship between the SAR pattern and the current mission. The parameters to be entered for the calculation are technical, generally mathematical, parameters (position, distance, angles, etc.) and are not parameters oriented toward a mission (for example to save a pilot lost after a crash). This leads to wasted time for the operator, who must re-enter a trajectory if he or she considers the latter not to be optimal with respect to the search area;
wasted time for the pilot who must concentrate on flight management rather than on successfully accomplishing the mission;
the calculation of the trajectories does not take environmental parameters, such as current drift or wind strength for a SAR at sea, into account;
lastly, these technical parameters have to be entered manually, which leads to wasted time for an operator.
It is therefore apparent that the cognitive load linked to the operations is substantial and takes up a lot of the operator's time. He or she must, in particular, estimate the orientation and form of the SAR trajectory pattern, and anticipate sea currents and other environmental parameters. However, during a search and rescue mission, the “time” parameter is very important, the operator having to act quickly to maximize the chance of mission success.